Automatic container locking apparatus for trailers

ABSTRACT

The object of this invention is to provide an automatic container locking apparatus for trailers. This locking apparatus is automatically operable in response to the weight of a container to lock or unlock the container on the deck of a trailer. This locking apparatus has a housing ( 10 ) vertically set in the deck ( 1 ), with a spring-biased actuator ( 20 ) movably set within the housing ( 10 ). A spring-biased locking bolt ( 30 ) having a top head ( 31 ) is movably set within the actuator ( 20 ). This locking bolt ( 30 ) has a stopper ( 32 ) and a curved guide slit ( 41 ), thus being selectively moved together with the actuator ( 20 ) while being rotated. A support shaft ( 50 ) holds the vertical position of the locking bolt ( 30 ) within the housing ( 10 ). An actuation pin ( 51 ) of the shaft ( 50 ) engages with the curved guide slit ( 41 ), thus allowing the locking bolt ( 30 ) to be rotatable when the locking bolt is vertically moved together with the actuator ( 20 ).

This is a nationalization of PCT/KR01/00082 filed Jan. 18, 2001 andpublished in English.

TECHNICAL FIELD

The present invention relates, in general, to an automatic containerlocking apparatus for trailers and, more particularly, to an automaticcontainer locking apparatus, installed in the deck of a trailer andautomatically operable in response to the weight of a container to lockor unlock the container on the deck of the trailer, thus securely andsafely holding the container on the deck while transporting thecontainer on a road, and being convenient to workers while loading orunloading the container onto or from the deck of the trailer.

BACKGROUND ART

As well known to those skilled in the art, a container is a large,vanlike, reusable box for consolidating smaller crates or cartons into asingle shipment, designed for easy and fast loading and unloading offreight. Such a container is loaded on a trailer, and is transported bya truck tractor on a road In order to hold such a container on the deckof a trailer while transporting the container on a road, a plurality oflocking apparatuses are installed in the deck at predeterminedpositions. Such an installation of the locking apparatuses on the deckof a trailer is prescribed by law.

FIGS. 1a and 1 b are sectional views, showing an operation of aconventional container locking apparatus for trailers when the lockingapparatus locks a container in position on the deck of a trailer. Asshown in the drawings, the conventional container locking apparatus,installed in the deck 1 of a trailer at a predetermined position,comprises a locking bolt 2. This locking bolt 2 is vertically movableand rotatable by an actuation of a lever 3, thus locking or unlocking acontainer 4 on the deck 1. In order to lock the container 4 to the deck1, the container 4 is primarily seated on the deck 1 at a predeterminedposition. Thereafter, the lever 3 of the locking bolt 2 is manipulatedby a worker to fully insert the top head 2′ of the locking bolt 2 into alocking hole 5 formed on the bottom of the deck 1, thus locking thecontainer 4 in position on the deck 1.

Therefore, the locking apparatus holds the container 4 on the deck 1 ofthe trailer while transporting the container on a road, and prevents thecontainer 4 from being undesirably moved on the deck 1 or unexpectedlydropped from the deck 1 onto the road during such transportation.

However, such conventional container locking apparatuses for trailersare somewhat difficult to manipulate, and so some workers or drivers oftruck tractors often neglect to lock the containers in position on thedecks of trailers. When a container is transported on a road while beingnot locked to the deck of a trailer as described above, the containermay be undesirably moved on the deck or unexpectedly dropped from thedeck onto the road. Particularly when the truck tractor, with thetrailer seating a container thereon without being locked to the deck ofthe trailer, turns a corner or encounters an uneven surface of a road,the container may be more easily removed from the deck 1 to cause severetraffic accidents.

DISCLOSURE OF THE INVENTION

Accordingly, the present invention has been made keeping in mind theabove problems occurring in the prior art, and an object of the presentinvention is to provide an automatic container locking apparatus fortrailers, which is installed in the deck of a trailer, and isautomatically operable in response to the weight of a container to lockor unlock the container on the deck when it is desired to load or unloadthe container onto or from the deck.

In order to accomplish the above object, the present invention providesan automatic container locking apparatus for trailers, comprising ahousing vertically set in the deck of a trailer at a predeterminedposition, an actuator having a hollow structure with a central opening,the actuator being axially and movably set within the housing whilebeing normally biased upward by a first compression coil spring suchthat the actuator is vertically extendible and retractable relative tothe upper end of the housing, a longitudinal locking bolt having a headat its upper end and movably and concentrically set within the centralopening of the actuator such that the locking bolt is removably insertedinto a locking hole of a container at the head, with a stopperexternally formed on the sidewall of the locking bolt at a predeterminedposition to selectively come into contact with the lower surface of theactuator, thus allowing the locking bolt to be selectively andvertically movable in conjunction with a vertical movement of theactuator, a hole longitudinally formed at the center of the locking boltwhile extending from the lower end of the locking bolt to apredetermined depth, with a curved guide slit formed on the sidewall ofthe locking bolt to communicate with the hole, a support shaftvertically standing within the housing while being fixed to the bottomlid of the housing at its lower end, the support shaft being axially,upwardly and movably inserted into the hole of the locking bolt from thelower end of the locking bolt, with a second spring set within the holeof the locking bolt to normally bias the locking bolt upward, and anactuation pin formed on the sidewall of the support shaft at an upperportion, and movably engaging with the curved guide slit of the lockingbolt, thus allowing the locking bolt to be rotatable relative to theactuator at a predetermined angle when the locking bolt is verticallymoved in response to external pressure applied from the containerdownward to the actuator.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which.

FIGS. 1a and 1 b are sectional views, showing an operation of aconventional container locking apparatus for trailers when the lockingapparatus locks a container in position on the deck of a trailer;

FIG. 2 is an exploded perspective view of an automatic container lockingapparatus for trailers in accordance with the preferred embodiment ofthe present invention;

FIGS. 3 and 4 are a perspective view and a sectional view of thecontainer locking apparatus of this invention, with the parts of thelocking apparatus completely assembled into a single body;

FIGS. 5a to 5 c are sectional views, showing an operation of thecontainer locking apparatus of this invention when the locking apparatuslocks a container in position on the deck of a trailer;

FIG. 6 is a position of the container locking apparatus of thisinvention when a container, which does not have any locking hole and isnot necessary to be locked to the deck, is seated on the deck; and

FIG. 7 is an exploded perspective view of an automatic container lockingapparatus for trailers, with a housing of the apparatus altered in itsprofile in accordance with a modification of the preferred embodiment ofthis invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Reference now should be made to the drawings, in which the samereference numerals are used throughout the different drawings todesignate the same or similar components.

FIG. 2 is an exploded perspective view of an automatic container lockingapparatus for trailers in accordance with the preferred embodiment ofthe present invention. FIGS. 3 and 4 are a perspective view and asectional view of the container locking apparatus of this invention,with the parts of the locking apparatus completely assembled into asingle body As shown in the drawings, the automatic container lockingapparatus for trailers of this invention comprises a housing 10, whichis vertically set in the deck of a trailer at a predetermined position.A cylindrical actuator 20, having a hollow structure with a steppedcentral opening 21 formed at the center of the actuator 20, is axiallyand movably set within the housing 10 while being normally biased upwardby a first compression coil spring 22 such that the actuator 20 isextendible and retractable relative to the upper end of the housing 10 Alongitudinal locking bolt 30, having a head 31 at its upper end, ismovably and concentrically set within the central opening 21 of theactuator 20 such that the locking bolt 30 is removably inserted into alocking hole of a container at the head 31. A stopper 32 is externallyformed on the sidewall of the locking bolt 30 at a predeterminedposition to selectively come into contact with the lower surface of theactuator 20, thus allowing the locking bolt 30 to be selectively andvertically movable in conjunction with a vertical movement of theactuator 20.

A hole 40 is longitudinally formed at the center of the locking bolt 30.This hole 40 extends from the lower end of the locking bolt 30 to apredetermined depth A guide slit 41, having a curved profile, is formedon the sidewall of the locking bolt 30 to communicate with the hole 40.This curved guide slit 41 allows the locking bolt 30 to be rotatablerelative to the actuator 20 at a predetermined angle as will bedescribed later herein when the locking bolt 30 is moved in response toexternal pressure applied downward to the locking bolt 30.

A support shaft 50 is axially, upwardly and movably inserted in the hole40 of the locking bolt 30 from the lower end of the locking bolt 30,with a second compression coil spring 52 set within the hole 40 at aposition between the inside end of the hole 40 and the top end of thesupport shaft 50. The lower end of the housing 10 is firmly closed by abottom lid 11, while the support shaft 50 is fixed to the bottom lid 11at its lower end. An actuation pin 51 is formed on a sidewall of thesupport shaft 50 at an upper portion, and movably engages with thecurved guide slit 41, thus allowing the locking bolt 30 to be rotatablerelative to the actuator 20 at the predetermined angle when the lockingbolt 30 is vertically moved.

FIGS. 5a to 5 c are sectional views, showing an operation of thecontainer locking apparatus of this invention when the locking apparatuslocks a container in position on the deck of a trailer As shown in thedrawings, the housing 10 of this locking apparatus is set in the deck 1of a trailer at a predetermined position. When the locking apparatus ofthis invention is free from any downward pressure, the actuator 20 andthe locking bolt 30, normally biased upward by the first and secondcompression coil springs 22 and 52, are elastically and commonlyprojected upward from the top surface of the deck 1, thus accomplishinga normal position of the locking apparatus as shown in FIG. 5a.

That is, in the normal position of the locking apparatus of FIG. 5a, theactuator 20, movably set within the housing 10, is projected to itsfully extended position outside the upper end of the housing 10 due tothe restoring force of the first compression coil spring 22. The firstspring 22 is set within the housing at a position between the lowersurface of the actuator 20 and the bottom lid 11 of the housing 10 Inthe normal position, the locking bolt 30, movably set within theactuator 20, is also projected to its fully extended position outsidethe upper end of the actuator 20 due to the restoring force of thesecond compression coil spring 52. In such a case, the support shaft 50,fixedly standing at the center of the bottom lid 11, maintains thevertical position of the locking bolt 30, while the second spring 52within the hole 40 of the locking bolt 30 biases the locking bolt 30upward In the normal position of the locking apparatus, the projectionalextension of the locking bolt 30 is limited by an engagement of the pin51 of the support shaft 50 with the guide slit 41 of the locking bolt30.

Such a normal position of the locking apparatus of FIG. 5a is designedsuch that the gap “d” between the lower surface of the actuator 20 andthe upper surface of the stopper 32 of the locking bolt 30 is equal tothe thickness “T” of a steel plate of the container 4 at a positionaround the locking hole 5. That is, the normal position of the lockingapparatus is set to accomplish an expression “d=T”. When a container 4is seated on the deck 1 such that the locking hole 5 is aligned with thehead 31 of the locking bolt 30, downward pressure is applied from thecontainer 4 to the upper surface of the actuator 20 The actuator 20 isthus primarily moved down within the housing 10 by a predetermineddistance equal to the gap “d” between the stopper 32 and the actuator20, while the locking bolt 30 is not moved. Therefore, the head 31 ofthe locking bolt 30 is completely inserted into the locking hole 5 ofthe container 4 at the initial stage of loading the container 4 on thedeck 1 The locking apparatus thus accomplishes a primary lockingposition, at which the stopper 32 comes into contact with the lowersurface of the actuator 20 as shown in FIG. 5b. In such a case, thelocking hole 5 formed on the steel plate of the container 4 is designedto have a rectangular profile capable of smoothly passing the head 31 ofthe locking bolt 30 through it when the head 31 is properly aligned withthe hole 5.

When downward pressure is further applied from the container 4 to theactuator 20 of FIG. 5b, the locking bolt 30 is moved downward along withthe actuator 20 since the stopper 32 comes into contact with the lowersurface of the actuator 20. During such a downward movement of thelocking bolt 30 along with the actuator 20, the locking bolt 30 is alsorotated relative to the actuator 20 at a predetermined angle since theactuation pin 51 of the fixed support shaft 50 movably engages with thecurved guide slit 41 of the rotatable locking bolt 30. The head 31 ofthe rotated locking bolt 30 thus crosses the rectangular locking hole 5of the container 4, and so the container 4 is completely locked to thedeck 1 The locking apparatus thus accomplishes a final locking positionas shown in FIG. 5c. In such a case, the rotated angle of the lockingbolt 30 relative to the fixed support shaft 50 has to be properly setsuch that the head 31 crosses the rectangular locking hole 5 of thecontainer 4. Therefore, the locking apparatus of this invention isautomatically operated in response to the weight of the container 4 tolock the container 4 in position on the deck 1 of the trailer.

FIG. 6 is a position of the container locking apparatus of thisinvention when a container, which does not have any locking hole and isnot necessary to be locked to the deck, is seated on the deck. As shownin the drawing, when such a container 4, which does not have any lockinghole and is not necessary to be locked to the deck, is seated on thedeck 1, the head 31 of the locking bolt 30 is fully retracted into thehousing 10 to allow the lower surface of the container 4 to be stablylaid on the top surface of the deck 1 without being interfered with thelocking bolt 30. Such a fully retractable structure of the locking bolt30 also protects the locking bolt 30 from unexpected damage or breakage.

FIG. 7 is an exploded perspective view of an automatic container lockingapparatus for trailers, with a housing of the apparatus altered in itsprofile in accordance with a modification of the preferred embodiment ofthis invention In this modification, the housing 10 is designed to havea rectangular cross-section different from the circular cross-section ofFIG. 2. Of course, it should be understood that the housing 10 may besomewhat freely designed to have another profile in place of such acircular cross-section or rectangular cross-section without affectingthe functioning of this invention.

When the container 4 is lifted upward from the deck 1 of the trailer tounload the container 4 from the deck 1, the downward pressure isreleased from the actuator 20, and so the locking apparatusautomatically returns to its normal position due to the restoring forceof the two compression coil springs 22 and 52. Therefore, it is possiblefor the locking apparatus to automatically release the container 4 whenit is desired to unload the container 4 from the deck 1.

INDUSTRIAL APPLICABILITY

As described above, the present invention provides an automaticcontainer locking apparatus for trailers This automatic containerlocking apparatus is installed in the deck of a trailer, and isautomatically operable in response to the weight of a container to lockor unlock the container on the deck of the trailer. Therefore, thelocking apparatus of this invention securely and safely holds thecontainer on the deck while transporting the container on a road, and isconvenient to workers while loading or unloading the container onto orfrom the deck of the trailer.

Although the preferred embodiments of the present invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

What is claimed is:
 1. An automatic container locking apparatus fortrailers, comprising: a housing vertically set in a deck of a trailer ata predetermined position; an actuator having a hollow structure with acentral opening, said actuator being axially and movably set within saidhousing while being normally biased upward by a first spring such thatthe actuator is vertically extendible and retractable relative to anupper end of said housing; a longitudinal locking bolt having a head atits upper end and movably and concentrically set within said centralopening of the actuator such that the locking bolt is removably insertedinto a locking hole of a container at said head, with a stopperexternally formed on a sidewall of said locking bolt at a predeterminedposition to selectively come into contact with a lower surface of theactuator, thus allowing the locking bolt to be selectively andvertically movable in conjunction with a vertical movement of theactuator; a hole longitudinally formed at a center of said locking boltwhile extending from a lower end of the locking bolt to a predetermineddepth, with a curved guide slit formed on the sidewall of said lockingbolt to communicate with the locking bolt hole; a support shaftvertically standing within said housing while being fixed to a bottomlid of the housing at its lower end, said support shaft being axially,upwardly and movably inserted into the hole of said locking bolt from alower end of the locking bolt, with a second spring within the hole ofthe locking bolt to normally bias the locking bolt upward; and anactuation pin formed on a sidewall of said support shaft at an upperportion of said support shaft, and movably engaging with said curvedguide slit of the locking bolt, thus allowing the locking bolt to berotatable relative to the actuator at a predetermined angle when thelocking bolt is vertically moved in response to external pressureapplied from the container downward to the actuator.